JP2629912B2 - Anti-slip device for vehicles - Google Patents

Description

Description of the Invention (Object of the Invention) (Industrial application field) The present invention relates to a device for preventing acceleration slip of a vehicle.

2. Description of the Related Art Conventionally, there has been known an acceleration slip prevention device (traction control device) for preventing a drive wheel from slipping when a vehicle is rapidly accelerated. In such a traction control device, the slip ratio S is controlled so that when the acceleration slip of the drive wheel is detected, the coefficient of friction μ between the tire and the road surface falls within the maximum range (the hatched range in FIG. 18). Here, the slip ratio S is “(VF−VB)
/ VF] × 100 (percent), VF is the wheel speed of the drive wheel, and VB is the vehicle speed. That is, when the slip of the drive wheel is detected, the engine output is controlled so that the slip ratio S falls within the hatched range, and the friction coefficient μ between the tire and the road surface is controlled so as to fall within the maximum range. It prevents the slip of the driving wheels during acceleration to improve the acceleration performance of the vehicle.

(Problems to be Solved by the Invention) In such a traction control device, if the conditions for terminating the slip control are not appropriate, even if the acceleration slip converges, the engine output control is continued and the acceleration performance is reduced, Problems such as the occurrence of acceleration slip again due to the end of the slip control during the engine output control occur.

Therefore, conventionally, a traction control device that ends the slip control when the wheel speed VF, the slip rate S, and the slip change rate ΔS of the drive wheels are all equal to or less than a predetermined threshold has been considered. However, the wheel speed V
Since F, slip rate S, and slip change rate ΔS are all obtained based on the sensor data of the driving wheel speed sensors, the above-described slip control must be performed at an appropriate timing according to various road surface conditions and driving conditions. With the drive wheel speed sensor alone, the amount of information is small, and the slip control is not performed at an accurate timing. For this reason, there arise problems such as, for example, that the slip control is terminated early and the slip control is not sufficient, or that the slip control is prolonged and sufficient acceleration is not secured. Further, if the start / end of the slip control is determined based only on the drive wheel speed sensor, if the drive wheel speed sensor becomes abnormal, the normal slip control is not performed.

The present invention has been made in view of the above points, and its object is to always end slip control at an appropriate timing in response to various road surface conditions and driving conditions, to reliably prevent the occurrence of slip, and to provide a vehicle. It is an object of the present invention to provide an acceleration slip prevention device for a vehicle, which can improve the acceleration of the vehicle.

[Structure of the Invention] (Means and Actions for Solving the Problems) That is, the vehicle acceleration slip prevention device according to the present invention is a drive wheel slip amount detection unit that detects a slip amount generated in a drive wheel based on a drive wheel speed. And a plurality of types of different driving information detected by different driving information detecting means, and at least two driving information detected by the driving information detecting means are independently determined in advance by a determination condition. Control end determination means for ending drive torque control according to the slip amount detected by the drive wheel slip amount detection means when the control end condition is satisfied. The driving means includes a driving torque detecting means for detecting a driving torque of the engine. Has been the driving torque of the engine is below the maximum torque road surface friction coefficient does not occur slip ultra-low μ road is not zero, is intended to include.

(Embodiment) Hereinafter, an acceleration slip prevention device for a vehicle according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1A is a configuration diagram showing an acceleration slip prevention device for a vehicle. The figure shows a front wheel drive vehicle, WFR is a front right wheel, WFL is a front left wheel, WRR is a rear right wheel,
WRL indicates a rear left wheel. Reference numeral 11 denotes a wheel speed sensor for detecting the wheel speed VFR of the front right wheel (drive wheel) WFR, and reference numeral 12 denotes the wheel speed V of the front left wheel (drive wheel) WFL.
A wheel speed sensor 13 for detecting the FL, a wheel speed sensor 13 for detecting the wheel speed VRR of the rear right wheel (driven wheel) WRR, 14
Is a wheel speed sensor for detecting the wheel speed VRL of the rear left wheel (driven wheel) WRL. The wheel speeds VFR, VFL, VRR, VRL detected by the wheel speed sensors 11 to 14 are input to the traction controller 15. The traction controller 15 sends a control signal to the engine 16 to perform control to prevent slippage of the drive wheels during acceleration.

FIG. 1 (B) shows an intake system of the engine 16, in which 21 is an air cleaner, 22 is an intake pipe, and the intake pipe 22 is mainly operated by an accelerator pedal. In addition to the throttle valve THm23, an auxiliary throttle valve THs24 whose opening is controlled by a control signal θs from the traction controller 15 is provided.
That is, the intake air introduced through the air cleaner 21 flows to the intake valve side through the auxiliary throttle valve THs24 and the main throttle valve THm23 in series, and the opening degree of the auxiliary throttle valve THs24 is determined by the traction controller 15 from the traction controller 15. The motor drive circuit 25 and its motor 24
The driving force of the engine 16 is controlled through M. Here, the opening degrees of the main throttle valve THm23 and the sub throttle valve THs24 are detected by the main throttle position sensor 26 and the sub throttle position sensor 27, respectively. The main throttle valve THm23 is provided with a main throttle idle SW28 for detecting a non-depressed state of the accelerator pedal, and the sub throttle valve THs24 is provided with a sub throttle fully open SW29. Further, an air flow sensor 30 for detecting an intake air amount is provided downstream of the air cleaner 21, and output signals from these sensors 26, 27, 30 and SWs 28, 29 are:
Either is given to the traction controller 15.

On the other hand, in FIG. 1 (A), reference numeral 17 denotes a front right wheel WFR.
Wheel cylinder for braking, 18 is the front left wheel W
Wheel cylinder that performs FL braking. Normally, pressure oil is supplied to these wheel cylinders via a master cylinder or the like (not shown) by operating a brake pedal (not shown). During traction control operation, pressure oil can be supplied from another route described below. The supply of pressure oil from the hydraulic pressure source 19 to the wheel cylinder 17 is performed via an in-red valve 17i, and the discharge of pressure oil from the wheel cylinder 17 to the reservoir 20 is performed via an out-red valve 17o. The supply of pressure oil from the hydraulic pressure source 19 to the wheel cylinder 18 is performed through an inlet valve 18i.
The outlet of pressure oil from the reservoir 20 to the reservoir 20 is
done through o. And the above inlet valve 17i
And 18i, the opening / closing control of the outlet valves 17o and 18o is performed by the traction controller 15.

Here, the driving force control of the engine 16 and the driving wheel WFR
The slip prevention control by the brake control of the WFL 12 is started / terminated by a combination of independent control start determination conditions based on signals from various sensors for detecting a plurality of different operating states.

Next, a detailed configuration of the traction controller 15 will be described with reference to FIG. Wheel speed sensor 11
The wheel speeds VFR and VFR of the drive wheels detected in
The FL is sent to a high vehicle speed selecting section (SH) 31, and a higher wheel speed is selected and output from the wheel speed VFR and the wheel speed VFL. At the same time, the wheel speeds VFR and VFL of the drive wheels detected by the vehicle speed sensors 11 and 12 are averaged in an averaging unit 32 to calculate an average wheel speed (VFR + VFL) / 2. The wheel speed output from the high vehicle speed selection unit 31 is multiplied by a variable KG in a weighting unit 33, and the average wheel speed output from the averaging unit 32 is multiplied by a variable (1-KG) in a weighting unit 34, and each is added. It is sent to the section 35 and added to make the driving wheel speed VF. Note that the variable KG is the third
As shown in the figure, it is a variable that changes according to the centripetal acceleration GY. As shown in FIG. 3, the centripetal acceleration GY is set so as to be proportional to the centripetal acceleration up to a predetermined value (for example, 0.1 g), and to become "1" when it exceeds the centripetal acceleration.

The wheel speeds of the driven wheels detected by the wheel speed sensors 13 and 14 are input to the low vehicle speed selection unit 36, and the smaller wheel speed is selected. Further, the wheel speed sensor 1
The wheel speeds of the driven wheels detected in 3 and 14 are input to the high vehicle speed selection unit 37, and the larger wheel speed is selected. Then, the smaller wheel speed selected by the low vehicle speed selector 36 is multiplied by the variable Kr in the weighting unit 38, and the larger wheel speed selected by the high vehicle speed selector 37 is weighted by the weighting unit 39.
Is multiplied by the variable (1-Kr). This variable Kr is the fourth
As shown in the figure, it changes between “1” to “10” according to the centripetal acceleration GY.

Further, the wheel speeds output from the weighting unit 38 and the weighting unit 39 are added in an adding unit 40 to be a driven wheel speed VR, and the driven wheel speed VR is further multiplied by a multiplication unit 40 '.
Is multiplied by (1 + α) to obtain the target drive wheel speed Vφ.

The drive wheel speed VF output from the adder 35
And the target driving wheel speed Vφ output from the multiplication unit 40 'is subtracted by the subtraction unit 41 to obtain the slip amount DVi' (= VF-
Vφ) is calculated. The slip amount DVi 'is further corrected in the adder 42 in accordance with the centripetal acceleration GY and the rate of change GY of the centripetal acceleration ΔGY. That is, a slip correction amount Vg that changes according to the centripetal acceleration GY as shown in FIG. 5 is set in the slip amount correction unit 43, and a centripetal acceleration as shown in FIG. A slip correction amount Vd that changes according to the change rate ΔGY of GY is set. Then, the addition unit 42 adds the slip correction amounts Vd and Vg to the slip amount DVi 'output from the subtraction unit 41 to obtain the slip amount DVi.

The slip amount DVi is sent to the calculation unit 45a in the TSn calculation unit 45 at a sampling time T of, for example, 15 ms, and
DVi is integrated while being multiplied by the coefficient KI to obtain the correction torque TS
n 'is required. That is, a correction torque obtained by correcting the slip amount DVi, that is, an integral correction torque TSn 'is obtained as TSn' = ΣKI.DVi (KI is a coefficient that changes in accordance with the slip amount DVi). The integral type correction torque TSn 'is applied to the drive wheels WFR and WFL.
Correction value for the torque for driving the engine 16
It is necessary to adjust the control gain in accordance with the change of the characteristic of the power transmission mechanism between the drive wheels and the drive wheels due to the change of the shift speed. Then, the corrected integrated correction torque TSn corresponding to the gear position is calculated.

In addition, the slip amount DVi is calculated by T
The correction torque TPn ′ is sent to the calculation section 46a of the Pn calculation section 46 and corrected by the slip amount DVi to be calculated. That is, a correction torque corrected by the slip amount DVi, that is, a proportional correction torque TPn 'is obtained as TPn' = DVi.Kp (Kp is a coefficient). Then, the proportional correction torque TPn ′ is multiplied by a coefficient GKp that is different depending on the speed in the coefficient multiplying unit 46b for the same reason as the integral correction torque TSn ′, and the corrected proportional correction is performed according to the speed. The torque TPn is calculated.

Further, the driven wheel speed VR output from the adder 40 is input to the reference torque calculator 47 as the vehicle speed VB.
Then, the vehicle acceleration calculation section in the reference torque calculation section 47
At 47a, the acceleration VB (GB) of the vehicle speed is calculated.

Then, the vehicle body acceleration VB (GB) calculated by the vehicle body acceleration calculating section 47a is passed through a filter 47b and becomes a vehicle body acceleration GBF. In the filter 47b, the fifteenth filter
In order to quickly shift to the state of the position “2” when the acceleration is increased in the state of the position “1” in FIG.
The average of the output of GBFn- ₁ and the currently detected GBn is equalized with the same weight, and GBFn = (GBn + GBFn- ₁ ) / 2 (1). In addition, when the acceleration is decreased due to the slip ratio S> S1 (S1 is set to a value slightly smaller than the maximum slip ratio Smax), for example, when shifting from the “2” position to the “3” position, it is delayed. Filter 47b to transition
Is switched to a slower filter. That is, GBFn = (GBn + 7GBFn- ₁ ) / 8 (2), and the weight is placed on the output of the previous filter 47b.

When the acceleration is reduced with the slip ratio S ≦ S1, that is, when the acceleration is reduced in the region of “1”, Sm is as small as possible.
To want to stay at ax, filter 47b is switched to a slower filter. That is, GBFn = (GBn + 15GBFn- ₁ ) / 16 (3), and the weight of the output of the previous filter 47b is very high. As described above, in the filter 47b, the filter 47b is switched in three stages as shown in the above equations (1) to (3) according to the state of the acceleration. Then, the vehicle body acceleration GBF is sent to the reference torque calculation unit 47c, and the reference torque TG is calculated. That is, TG = GBF × W × Re is calculated. Here, W is the vehicle weight, and Re is the tire radius.

The reference torque TG and the integral correction torque T
The subtraction with Sn is performed in the subtraction unit 48, and the subtraction with the proportional correction torque TPn is performed in the subtraction unit 49. Thus, the target torque Tφ is calculated as Tφ = TG−TSn−TPn.

Since the target torque Tφ indicates the torque for driving the drive wheels WFR and WFL, the target torque Tφ is divided by the total gear ratio between the engine 16 and the drive wheels in the engine torque calculation unit 50 and converted into the target engine torque Tφ ′. . And
The target engine torque Tφ 'is the lower limit value Rl of the engine torque.
In the lower limit value setting section 51 which sets im, the target engine torque Tφ ′ is obtained by the lower limit Tlim that changes according to the elapsed time t from the start of the traction control or the vehicle speed VB as shown in FIG. 16 or FIG. Is limited. Then, the target engine torque Tφ ′ for which the lower limit value of the engine torque is set by the lower limit value setting unit 51.
Is sent to the torque / throttle opening degree converter 52 to obtain the opening degree θs of the sub throttle valve for generating the target engine torque Tφ ′. Then, by adjusting the opening degree θs of the auxiliary throttle valve, the output torque of the engine is controlled so as to become the target engine torque Tφ ′.

The wheel speeds VRR and VRL of the driven wheels are calculated by a centripetal acceleration calculation unit.
Sent to 53 to determine the degree of turning, the centripetal acceleration G
Y 'is required. The centripetal acceleration GY 'is sent to the centripetal acceleration correction unit 54, and the centripetal acceleration GY' is corrected according to the vehicle speed.

That is, GY = Kv · GY ′, and the coefficient Kv changes according to the vehicle speed as shown in FIGS. 7 to 12, whereby the centripetal acceleration GY is corrected according to the vehicle speed.

By the way, the larger driven wheel speed output from the high vehicle speed selector 37 is subtracted from the wheel speed VFR of the drive wheel by the subtractor 55. Further, the larger wheel speed output from the high vehicle speed selector 37 is subtracted from the wheel speed VFL of the drive wheel by the subtractor 56.

The output of the subtraction unit 55 is multiplied by KB (0 <
KB <1), the output of the subtractor 56 is multiplied by (1−KB) in the multiplier 58, and then added in the adder 59 to obtain the slip amount DVFR of the right driving wheel. At the same time,
The output of the subtraction unit 56 is multiplied by KB in the multiplication unit 60, the output of the subtraction unit 55 is multiplied by (1−KB) in the multiplication unit 61 and then added in the addition unit 62 to obtain the slip amount DVFL of the left driving wheel. It is said. The variable KB changes according to the elapsed time from the start of the traction control as shown in FIG. 13, and is set to "0.5" at the start of the traction control, and becomes "0.8" as the traction control is advanced. ". For example, when KB is set to “0.8”, the brake control is performed by recognizing that when one of the driving wheels slips, the other driving wheel slips by 20% of one driving wheel. I have to. This is because if the brakes on the left and right drive wheels are completely independent, if only one of the drive wheels is braked and the rotation decreases, the differential drive wheel will slip and the brake will be applied this time due to the action of the differential. This is because it is not preferable to be repeated. The slip amount DVFR of the right driving wheel is calculated by the differentiator 63.
And the temporal change amount, that is, the slip acceleration GFR is calculated, and the slip amount DVFL of the left driving wheel is differentiated in the differentiating section 6 to calculate the temporal change amount, that is, the slip acceleration GFL. . The slip acceleration GFR is calculated based on the amount of change in brake fluid pressure (Δ
P) It is sent to the calculation unit 65, and the GFR (GFL)-
The change amount ΔP of the brake fluid pressure for suppressing the slip acceleration GFR is obtained with reference to the ΔP conversion map. The amount of change ΔP of the brake fluid pressure is sent to the ΔP-T converter 67 to calculate the opening time T of the inlet valve 17i in FIG. 1 (A). Similarly, the slip acceleration G
FL is sent to the brake fluid pressure change amount (ΔP) calculation unit 66,
Referring to the GFR (GFL)-. DELTA.P conversion map shown in FIG. 14, the change amount .DELTA.P of the brake fluid pressure for suppressing the slip acceleration GFL is obtained. The change amount ΔP of the brake fluid pressure is sent to the ΔP-T converter 68 to calculate the opening time T of the inlet valve 18i in FIG. 1 (A).

In FIG. 14, when the brake is applied at the time of turning, in order to strengthen the brake of the drive wheel on the inner wheel side,
The inner wheel side at the time of turning is shown by a broken line a.

On the other hand, a switch S1 is interposed between the subtraction unit 49 for calculating the target torque Tφ and the engine torque calculation unit 50, and the brake hydraulic pressure change amount (ΔP) calculation units 65 and 66 are used for the ΔP-T conversion unit. Between 67 and 68, switch S2
a, S2b are interposed. The switches S1, S2a, S2b are closed / opened when slip control start / end conditions described later are satisfied, respectively.
S2b is controlled to be opened and closed by the control start / end determination unit 69. The control start / end determination unit 69 is supplied with a slip determination signal from the slip determination unit 70. The slip judging section 70 calculates the slip amount DV obtained by the adding section 42.
It is determined whether or not i exceeds a slip determination value α previously stored in the slip determination value storage unit 71 (in this case, α is determined by a map according to road surface conditions). The start / end determination unit 69 is provided. In addition, the control start / end determination section 69 has an ON / OFF signal from the main throttle idle SW 28 in FIG.
Starting with the off signal and the main throttle opening detection signal from the main throttle position sensor 26, the engine torque sensor
Torque detection signal from 72 and shift lever position switch
A position detection signal from 73, a clutch disconnection / connection detection signal from a clutch operation sensor 74, and a brake fluid pressure detection signal from a brake fluid pressure sensor 75 are provided.

Here, the control start / end determination unit 69 determines whether a slip determination signal (DVi> α) is obtained from the slip determination unit 70 or the torque detected by the engine torque sensor 72 is a predetermined torque value (for example, 4 kg · m: The maximum throttle value at which no slip occurs on a low μ road), the temporal change rate of the main throttle opening obtained by the main throttle position sensor 26, that is, the load operation speed of the access pedal is a plus predetermined value or more, or the main throttle idle SW 28 Is turned off,
When any three of the four control start conditions are satisfied, a control start signal is output, and the switches S1, S2a, and S2b are closed. The control start / end determination unit 69 determines whether a slip determination signal (DVi ≦ α) is obtained from the slip determination unit 70 or the torque detected by the engine torque sensor 72 is a predetermined torque value (for example, 4 kg · m: ultra-low μ). (The maximum torque value at which no slip occurs on the road), the main throttle opening obtained by the main throttle position sensor 26 is smaller than a predetermined judgment value, the main throttle idle SW 28 is turned off, or the shift lever position SW 73 is parked. Or in the neutral N position, whether the clutch operation sensor 74 is in the clutch disconnection detection position,
A control end signal is output when any three of the seven control end conditions, that is, whether the brake hydraulic pressure detection value obtained by the brake hydraulic pressure sensor 75 is equal to or higher than a predetermined hydraulic pressure value, are satisfied, and the switch S1 , S2a and S2b are opened.

Next, the operation of the acceleration slip prevention device for a vehicle according to the embodiment of the present invention configured as described above will be described. 1 and 2, the vehicle speed sensors 13, 14
The wheel speeds of the driven wheels (rear wheels) output from are input to a high vehicle speed selection unit 36, a low vehicle speed selection unit 37, and a centripetal acceleration calculation unit 53. In the low vehicle speed selection unit 36, the smaller wheel speed of the left and right wheels of the driven wheels is selected, and the high vehicle speed selection unit 37
In, the larger one of the left and right driven wheels is selected. During normal straight running, if the wheel speeds of the left and right driven wheels are the same, the low vehicle speed selection unit 36
The same wheel speed is selected from the high vehicle speed selection unit 37.
Further, the wheel speeds of the left and right driven wheels are input to the centripetal acceleration calculation unit 53, and the degree of turning when the vehicle is turning, that is, how steep the vehicle turns is based on the wheel speeds of the left and right driven wheels. Is calculated.

Hereinafter, how the centripetal acceleration is calculated in the centripetal acceleration calculation unit 53 will be described. In a front-wheel drive vehicle, since the rear wheels are driven wheels, the vehicle speed at that position can be detected by a wheel speed sensor regardless of slippage due to driving, so that Ackerman geometry can be used. That is, in the normal turning is calculated as centripetal acceleration GY 'is ^{GY' = v 2 / r ...} (4) (v = vehicle speed, r = radius of gyration).

For example, when the vehicle is turning to the right as shown in FIG. 19, the center of turning is Mo, the distance from the center of turning Mo to the inner wheel side (WRR) is r1, the tread is Δr, and the inner wheel is The wheel speed on the side (WRR) is set to v1, and the outer wheel side (WR
If the wheel speed of L) is v2, v2 / v1 = (Δr + r1) / r1 (5) Then, the above equation (5) is modified to obtain 1 / r1 = (v2−v1) / Δr · v1 (6). When the inner ring side is used as a reference, the centripetal acceleration G
Y ′ is calculated as GY ′ = vl ² / r1 = vl ² · (v2−v1) / Δr · v1 = v1 (v2−v1) / Δr (7)

That is, the centripetal acceleration GY 'is calculated by the seventh equation.
By the way, since the inner wheel speed v1 is smaller than the outer wheel speed v2 when turning, the centripetal acceleration GY 'is calculated using the inner wheel speed v1. Is done. Therefore, the coefficient KG multiplied by the weighting unit 33 is underestimated because the centripetal acceleration GY 'is underestimated. Therefore, the driving wheel speed VF
Is estimated to be small, the slip amount DVi '(VF-
Vφ) is also underestimated. Thus, since the target torque Tφ is largely estimated, the target engine torque is largely estimated, so that a sufficient driving force is applied even during turning.

By the way, in the case of extremely low speed, as shown in FIG. 19, the distance from the inner wheel side to the turning center M0 is r1,
In a vehicle that understeers as the speed increases, the center of turning shifts to M, and the distance is r (r> r1).
It has become. Even when the speed increases in this way, since the turning radius is calculated as r1, the centripetal acceleration GY 'calculated based on the above equation (7) is calculated as a value larger than the actual value. For this reason, the centripetal acceleration GY ′ calculated in the centripetal acceleration calculation unit 53 is sent to the centripetal acceleration correction unit 54, and the centripetal acceleration GY becomes small at high speed.
The centripetal acceleration GY 'is multiplied by the coefficient Kv in FIG. This variable Kv is set to be smaller in accordance with the vehicle speed,
The setting may be made as shown in FIG. 8 or FIG. Thus, the corrected centripetal acceleration GY is output from the centripetal acceleration correction unit 54.

On the other hand, as the speed increases, oversteer (r
<R1) In the vehicle, the centripetal acceleration correction unit 54 performs a correction completely opposite to that of the understeer vehicle described above. That is, any one of the variables Kv in FIGS.
Is used to correct the centripetal acceleration GY ′ calculated by the centripetal acceleration calculation unit 53 so as to increase as the vehicle speed increases.

By the way, the smaller wheel speed selected by the low vehicle speed selector 36 is multiplied by a variable Kr in the weighting unit 38 as shown in FIG. 4, and the high vehicle speed selected by the high vehicle speed selector 37 is weighted by the weighting unit 39. Is multiplied by the variable (1-Kr). The variable Kr is set to "1" at the time of turning so that the centripetal acceleration GY becomes larger than 0.9 g, for example.
Is set to “0” when becomes smaller than 0.4 g.

Accordingly, for turning such that the centripetal acceleration GY becomes greater than 0.9 g, the low vehicle speed wheel speed of the driven wheels output from the low vehicle speed selection unit 36, that is, the inner wheel speed at the time of selection is selected. You. Then, the weighting unit 38 and
The wheel speed output from 39 is added in an adder 40 to obtain a driven wheel speed VR, and the driven wheel speed VR is further multiplied by (1 + α) in a multiplier 40 ′ to obtain a target drive wheel speed V.
φ.

After the higher wheel speed of the drive wheel speeds is selected by the high vehicle speed selection unit 31, the weighting unit 33 multiplies it by the variable KG as shown in FIG. further,
The average vehicle speed of the drive wheels (VFR +
(VFL) / 2 is multiplied by (1−KG) in the weighting section 34, and is added to the output of the weighting section 33 in the adding section 35 to obtain the drive wheel speed VF. Therefore, if the centripetal acceleration GY is, for example, 0.1 g or more, KG = 1, so that the wheel speed of the larger one of the two drive wheels output from the high vehicle speed selection unit 31 is output. Become. That is,
The turning degree of the vehicle increases and the centripetal acceleration GY is, for example, 0.
When the weight is 9 g or more, "KG = Kr = 1", so that the driving wheel side uses the wheel speed of the outer wheel having a higher wheel speed as the driving wheel speed VF, and the driven wheel side uses the wheel speed of the inner wheel having a lower wheel speed. Is the driven wheel speed VR, the slip amount DVi ′ (= VF−Vφ) calculated by the subtraction unit 41 is largely estimated. Therefore, the target torque Tφ is estimated to be small, the output of the engine is reduced, the slip ratio S is reduced, the lateral force A can be increased as shown in FIG. 18, and the grip force of the tire at the time of turning is reduced. By raising it, a safe turn can be performed.

The slip amount DVi 'is added to the slip amount corrector 43 only at the time of turning when the centripetal acceleration GY occurs, as shown in FIG. 5, and the slip amount corrector 44 shown in FIG. Such a slip amount Vd is added. For example, assuming a curve turning at a right angle, the centripetal acceleration GY and its temporal change rate ΔGY have positive values in the first half of the turn, but the temporal change rate of the centripetal acceleration GY in the second half of the curve. ΔGY is a negative value. Accordingly, in the first half of the curve, the adder 42 adds the slip correction amount Vg shown in FIG.
(> 0) and the slip correction amount Vd (> 0) shown in FIG. 6 are added to obtain the slip amount DVi. In the latter half of the curve, the slip correction amount Vg (> 0) and the slip correction amount Vd
(> 0) is added to the slip amount DVi. Therefore, the slip amount DVi in the latter half of the turn is estimated to be smaller than the slip amount DVi in the first half of the turn, thereby reducing the engine output and increasing the lateral force in the first half of the turn, and in the latter half of the turn, The engine output is restored to improve the acceleration of the vehicle.

In this way, the corrected slip amount DVi is, for example, 1
It is sent to the TSn operation unit 45 with a sampling time T of 5 ms. In the TSn calculation unit 45, the slip amount DVi is integrated while being multiplied by the coefficient KI to obtain a correction torque TSn.

That is, a correction torque obtained by correcting the slip amount DVi, that is, an integral correction torque TSn is obtained as TSn = GKiΣKI · DVi (KI is a coefficient that changes in accordance with the slip amount DVi).

In addition, the slip amount DVi is calculated by T
The correction torque TPn is sent to the Pn calculation unit 46 and calculated.
That is, the correction torque corrected by the slip amount DVi, that is, the proportional correction torque TPn is obtained as TPn = GKpDVi · Kp (Kp is a coefficient).

Further, the values of the coefficients GKi, GKp used in the calculations in the coefficient multiplying units 45b, 46b are switched to values according to the gear position after the shift after a set time from the start of the shift when upshifting. This takes time from the start of the shift to the end of the shift after the shift stage is actually switched, and when shifting up, the above-mentioned coefficients GKi and GK corresponding to the high speed stage after the shift and the shift start
When p is used, the values of the correction torques TSn and TPn correspond to the above-mentioned high speed gears. Therefore, even though the actual shift is not completed, the value becomes smaller than the value before the start of the shift and the target torque Tφ increases. This is because the slip is induced and the control becomes unstable.

Further, the driven wheel speed VR output from the adder 40 is input to the reference torque calculator 47 as the vehicle speed VB.
Then, the acceleration VB (GB) of the vehicle speed is calculated in the vehicle acceleration calculation section 47a. Then, the acceleration GB of the vehicle speed calculated by the vehicle acceleration calculation unit 47a is, as described in the configuration of the filter 47b,
Any one of the filters of the equations (1) to (3) is applied to keep the GBF at an optimum position according to the state of the acceleration GB. Then, the reference torque calculating section 47c calculates a reference torque TG (= GBF × W × Re).

The reference torque TG and the integral correction torque T
Subtraction with Sn is performed in a subtraction unit 48, and the proportional correction torque TPn is further performed in a subtraction unit 49. Thus, the target torque Tφ is calculated as Tφ = TG−TSn−TPn.

This target torque Tφ is obtained when the switch S1 is closed.
That is, when the control start / end determination section 69 determines that the control start condition is satisfied, the control start / end determination section 69 gives the control torque to the engine torque calculation section 50 and converts it into the target engine torque Tφ ′. The target engine torque Tφ ′ is determined by the lower limit value setting unit 51 that sets the lower limit value Tlim of the engine torque, as shown in FIG. 16 or FIG. 17, by the elapsed time t from the start of traction control or the vehicle speed VB. Lower limit Tlim changes according to
As a result, the lower limit value of the target engine torque Tφ ′ is limited. In other words, even when the reference torque TG cannot be detected properly, such as at the start of the traction control limit or at a low speed, the torque lower limit value Tlim is set to be slightly larger as shown in FIG. 16 or FIG. It is possible to output an engine torque Tφ 'that is equal to or greater than the torque at which no slip occurs, thereby obtaining a favorable acceleration. This is because the engine torque Tφ ′ that is equal to or greater than the torque at which no slip occurs is output, and even when slip occurs, sleep is suppressed by brake control.

The target engine torque Tφ ′ for which the lower limit value of the engine torque is set by the lower limit value setting unit 51 is sent to the torque / throttle opening degree conversion unit 52, and an auxiliary throttle valve for generating the target engine torque Tφ ′ is provided. Of opening θ
s is required. Then, the opening degree θs of the sub throttle valve THs24 of the intake system in FIG.
By adjusting the output torque via the motor 24M, the output torque of the engine 16 is controlled so as to reach the target engine torque Tφ ′, and the maximum driving force that can be transmitted under the current road surface condition is generated.

By the way, the larger driven wheel speed output from the high vehicle speed selector 37 is subtracted from the wheel speed VFR of the drive wheel by the subtractor 55. Further, the larger wheel speed output from the high vehicle speed selector 37 is subtracted from the wheel speed VFL of the drive wheel by the subtractor 56. Therefore, the subtractor 55
And 56 are underestimated to reduce the number of times the brake is used even during turning, and reduce the slip of the drive wheels by reducing the engine torque.

The output of the subtraction unit 55 is multiplied by KB (0 <
KB <1), the output of the subtractor 56 is multiplied by (1−KB) in the multiplier 58, and then added in the adder 59 to obtain the slip amount DVFR of the right driving wheel. At the same time,
The output of the subtraction unit 56 is multiplied by KB in the multiplication unit 60, the output of the subtraction unit 55 is multiplied by (1−KB) in the multiplication unit 61 and then added in the addition unit 62 to obtain the slip amount DVFL of the left driving wheel. It is said. The variable KB changes according to the elapsed time t from the start of the traction control, as shown in FIG. 13, and is set to “0.5” at the start of the traction control. 0.8 ". That is, when the slip of the drive wheels is reduced by the brake, at the time of starting the control, the brakes are simultaneously applied to both the wheels, and for example, an unpleasant steering wheel shock at the start of the brake control on the split road can be reduced. . On the other hand, an operation in the case where the brake control is continuously performed and the KB becomes “0.8” will be described. In this case, when one of the drive wheels slips, the other drive wheel recognizes that the slip has occurred by 20% of the one drive wheel and performs the brake control. This is because if the brakes on the left and right drive wheels are completely independent, if only one of the drive wheels is braked and the rotation decreases, the differential drive wheel slips due to the action of the differential and the brake is applied. This is because it is not preferable to be repeated. The slip amount DVFR of the right driving wheel is differentiated by a differentiator 63 to calculate a temporal change amount thereof, that is, a slip acceleration GFR, and the slip amount DVFL of the left drive wheel is differentiated by a differentiator 64 to calculate the time. The target change amount, that is, the slip acceleration GFL is calculated. Then, the slip acceleration GFR is sent to the brake fluid pressure change amount (ΔP) calculation unit 65,
Referring to the GFR (GFL)-. DELTA.P conversion map shown in the figure, a change amount .DELTA.P of the brake fluid pressure for suppressing the slip acceleration GFR is obtained. Similarly, the slip acceleration G
FL is sent to the brake fluid pressure change amount (ΔP) calculation unit 66,
Referring to the GFR (GFL)-. DELTA.P conversion map shown in FIG. 14, the change amount .DELTA.P of the brake fluid pressure for suppressing the slip acceleration GFL is obtained.

Further, the change amount ΔP of the brake fluid pressure for suppressing the slip acceleration GFR output from the ΔP calculation section 65 is described.
Is supplied to a ΔP-T conversion unit 67 that calculates the opening time T of the inlet valve 17i when the switch S2a is closed, that is, when the control start / end determination unit 69 determines that the control start condition is satisfied. That is, the valve opening time T calculated by the ΔP-T converter 67 is used as the brake operation time FR of the right driving wheel WFR. Similarly, the change amount ΔP of the brake fluid pressure for suppressing the slip acceleration GFL output from the ΔP calculation unit 66 is determined when the switch S2b is closed, that is, the control start condition by the control start / end determination unit 69. ΔP−T for calculating the opening time T of the inlet valve 18i at the time of establishment determination
The conversion unit 68 is provided. That is, the ΔP-T conversion unit 68
The valve opening time T calculated in the above is different from the left driving wheel WFL.
Of the brake operation time FL. This suppresses the occurrence of the above-mentioned slip due to the left and right drive wheels WFR and WFL.

In FIG. 14, when the brake is applied at the time of turning, in order to strengthen the brake of the drive wheel on the inner wheel side,
The inner wheel side at the time of turning is shown by a broken line a. In this way, when the load shifts to the outer wheel side during turning and the inner wheel side is easily slipped, the brake fluid pressure change amount ΔP is made larger at the inner wheel side than at the outer wheel side, so that the It is possible to prevent the inner ring from slipping.

Here, FIGS. 20 (A) and (B) show flowcharts of the start determination and the end determination of the slip control, respectively. In FIG. 20 (A), condition A is the first four control start conditions,. , Is an OR condition, and condition B is three of the four control start conditions in the previous period, among the three control start conditions excluding the control start condition satisfied in condition A.
The condition C is an OR condition, and the condition C is the first four control start conditions,
, And are OR conditions of two control start conditions excluding the control start condition satisfied in condition A and the control start condition satisfied in condition B. For example, in a state where the vehicle is traveling on a low μ road such as an icy road, the acceleration of the engine output due to the depression of the access pedal causes the drive wheels WFR and WFL to accelerate the slip amount DVi (DVi> α) exceeding the slip determination value α. When a slip occurs, the engine torque sensor 72 detects an engine drive torque T of a predetermined torque value To (4 kg · m) or more due to the increase in the engine output, and the main throttle idle SW is turned off by depressing the access pedal. Thus, the three control start determination conditions are satisfied. Then, the switch S1 good for the control start / end determination unit 69
And S2a, S2b are closed, and the engine torque control according to the slip amount DV of the drive wheels WFR, WFL and the slip control by the braking control are started. In this case, even if the load operation speed of the accelerator pedal obtained by the main throttle position sensor 26 does not reach the plus predetermined value or more, it is determined that any one of the control start conditions is satisfied to determine the start of the slip control. Is performed.

On the other hand, in FIG. 20 (B), condition A is an OR condition of the previous seven control end conditions,,,,, and condition B is the first seven control end conditions,,,,.
,,, Are OR conditions of six control end conditions excluding the control end condition satisfied in condition A, and condition C is a control satisfied in condition A among the seven control end conditions,. This is an OR condition of five control end conditions excluding the end condition and the control end condition satisfied in the above condition B. In the state after the start of the slip control, the drive wheels WFR and WFL are set to the slip determination value α due to, for example, a decrease in engine output due to a full return operation of the accelerator pedal.
When the following slip amount DVi (DVi ≦ α) converges to an acceleration slip, the main throttle position sensor 26 detects that the main throttle opening becomes smaller than a predetermined determination value with the full return operation of the accelerator pedal, When the main throttle idle SW is turned on by the full return operation of the accelerator pedal, the three control end conditions are satisfied. Then, the switches S1 and S2a, S2b are controlled to close by the control start / end determination unit 69, and the drive wheels WFR, WFL
The engine torque control according to the slip amount DV and the slip control by the braking control are terminated. In this case, even if the engine torque sensor 72 does not detect the engine drive torque T less than the predetermined torque value To (4 kg · m) due to the decrease in the engine output, the shift lever position SW73 is shifted to the shift position of the parking P or the neutral N. The slip control is determined to be completed when any one of the above control termination conditions is satisfied, for example, when the control is shifted or when the hydraulic pressure by the brake pedal becomes equal to or more than a predetermined determination value.

Therefore, according to the acceleration slip prevention device having the above configuration, the start / end of the slip control is determined by the wheel speed sensor.
Slip amount DVi obtained according to the vehicle speed signal from 11-14
The engine drive torque obtained by the engine torque sensor 72, the opening state of the main throttle valve THm23 obtained by the main throttle idle SW 28, the opening degree of the main throttle valve THm obtained by the main throttle position sensor 26, the shift lever The shift position state obtained by the position SW 73, the clutch engagement state obtained by the clutch operation sensor 74, and the brake hydraulic pressure obtained by the brake hydraulic pressure sensor 75 are different from each other. Since the output characteristics of the above sensors and SWs differ according to the road surface conditions and driving conditions, the start / end determination of the slip control can be made accurately according to various road conditions and driving conditions. To prevent slippage and improve vehicle acceleration. It can be. Further, for example, even if an abnormality occurs in a certain sensor or SW, the start / end determination of the slip control can be accurately performed by satisfying the combination condition of the remaining sensors and SW.

In the embodiment, the end determination of the slip control is performed when any three of the seven independent control end conditions different from the input sensor or the SW are satisfied. In the case of using the control opening θs of the sub-throttle valve THs24 obtained by the sub-throttle position sensor 27, it is added that the control opening θs no longer affects the intake air amount obtained based on the output signal of the airflow sensor 30. Alternatively, the control opening degree θs and the engine drive torque obtained by the engine torque sensor 72 may be used, and instead of the control termination condition, the change in the control opening degree θs is equal to or less than a predetermined change amount and the engine An additional configuration that the reduction amount of the driving torque is equal to or more than a predetermined reduction amount may be added, or the main throttle position obtained by the main throttle position sensor 26 may be used. Liter with changing speed of the main throttle opening instead of the opening, may be the change rate relates direction of the opening decreases is larger than a predetermined value.

Further, although the slip determination unit determines whether the slip amount exceeds the slip determination value α, the slip ratio S may be used instead of the slip amount.

Further, in the above embodiment, the determination of the end of the slip control was made when three of the seven control end conditions were satisfied, but the setting of the conditions A, B, and C was changed in FIG. Three types of AND conditions of a plurality of conditions selected from the above seven control end conditions are set, and they are set as the respective conditions A, B, and C, and any of the above conditions A, B, and C is satisfied. Then, the determination of the end of the slip control may be made. For example, condition A is the first term control end condition,
AND condition, condition B is the previous term control end condition,
The ND condition and condition C may be set so as to satisfy the AND condition of the first-term control termination condition, and the control termination determination may be performed according to the flowchart shown in FIG. 20 (C).

[Effects of the Invention] As described in detail above, according to the present invention, the occurrence of slip is reliably suppressed by always ending slip control at an appropriate timing in response to various road surface conditions and driving conditions. In addition to the above, it is possible to suppress unnecessary drive torque reduction control, so that the acceleration of the vehicle is not impaired.

[Brief description of the drawings]

FIG. 1 (A) is an overall configuration diagram of an acceleration slip prevention device for a vehicle according to an embodiment of the present invention, and FIG.
FIG. 2A is a configuration diagram showing an engine intake system, and FIG.
FIG. 3 is a block diagram showing the control of the traction controller for each functional block, FIG. 3 is a diagram showing the relationship between the centripetal acceleration GY and a variable KG, and FIG.
FIG. 5 shows the relationship between the centripetal acceleration GY and the slip correction amount Vg, and FIG. 6 shows the relationship between the temporal change ΔGY of the centripetal acceleration and the slip correction amount Vd. 7 to 12 show the relationship between the vehicle speed VB and the variable Kv, respectively, and FIG. 13 shows the variable KB from the start of the brake control.
FIG. 14 is a diagram showing the relationship between the temporal change amount GFR (GFL) of the slip amount and the change amount ΔP of the brake fluid pressure, and FIGS. 15 and 18 show the slip ratio S and FIG. 16 is a diagram showing the relationship between the friction coefficient μ of the road surface, FIG. 16 is a diagram showing the Tlim-t characteristic, FIG. 17 is a diagram showing the Tlim-VB characteristic, FIG. 19 is a diagram showing the state of the vehicle at the time of turning, FIGS. 20 (A) and (B) are flowcharts respectively showing the start determination and the end determination of the slip control by the vehicle acceleration slip prevention device, and FIG. 20 (C) is a slip control according to another embodiment of the present invention. 9 is a flowchart showing the end determination of the process. WFR, WFL …… Drive wheel, WRR, WRL …… Driving wheel, 11-14 ……
Wheel speed sensor, 15 ... Traction controller, 16
… Engine, 17, 18… Wheel cylinder, 23… Primary throttle valve THm, 24… Secondary throttle valve THs, 26… Primary throttle position sensor, 27… Secondary throttle position sensor, 28… Primary throttle idle SW, 69 ……
Control start / end determination section, 70 Slip determination section, 71
Slip judgment value storage unit, 72 ... Engine torque sensor,
73: Shift lever position switch, 74: Clutch operation sensor, 75: Brake fluid pressure sensor, S1, S2a, S2b: Switch.

Continued on the front page (72) Inventor Makoto Shimada 5-33-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation (72) Inventor Katsunori 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors (56) References JP-A-63-31866 (JP, A) JP-A-61-67634 (JP, A)

Claims (1)

(57) [Claims] 1. A drive wheel slip amount detecting means for detecting a slip amount generated on a drive wheel based on a drive wheel speed; a separate drive information detecting means for detecting a plurality of types of different drive information; When each of the driving information detected by the driving information detecting means satisfies a control end condition in which a determination condition set in advance is independently set, a drive corresponding to a slip amount detected by the driving wheel slip amount detecting means is performed. A control end determining unit for ending the torque control, wherein the driving information detecting unit includes a driving torque detecting unit for detecting a driving torque of an engine; The driving torque of the engine detected by the torque detecting means is the maximum torque at which no slip occurs on an ultra-low μ road where the road surface friction coefficient is not zero. An acceleration slip prevention device for a vehicle, comprising: